Many technologies for supporting user's improvement of sport by utilizing sensing and analysis have been developed. In this technology, analyzing play of a user himself or herself or of another user statistically is used as one method. Thus, there is a proposed technology that automatically analyzes a motion by attaching a sensor device including sensors such as an acceleration sensor and a gyro sensor to a user or an item used by a user and analyzing sensing data acquired by the sensors (for example, refer to Patent Literature 1, etc.).
This sensor device can only include a battery of a small capacity because of its size in many cases, and frequent charging and battery exchange may impair fun of sport. On the other hand, if the sensor device is equipped with a large capacity battery to elongate an operation time of the sensor device, the weight of the sensor device itself becomes heavy, and has an influence on a user's play action of sport. Thus, there is a strong demand for electrical power saving of the sensor device provided in the item used by the user. For example, Patent Literature 2 discloses a technology of electric power control of a sensor.